The January 2016 issue of the journal Diabetes Care reported the outcome of a randomized trial that revealed a beneficial role for testosterone treatmentin men with diabetes.

“We hypothesized that testosterone may be an anti-inflammatory and insulin sensitizing agent since it has been known for some time that testosterone reduces adiposity and increases skeletal muscle,” remarked lead researcher Paresh Dandona, MD, PhD, who is a Distinguished Professor at the State University of New York and chief of endocrinology, diabetes and metabolism in the Department of Medicine in the Jacobs School of Medicine and Biomedical Sciences at the University of Buffalo. “Our previous work has shown that obesity is associated with oxidative stress and inflammation, and inflammatory mediators are known to interfere with insulin signaling.”

The trial included 94 type 2 diabetic men, among whom 44 had low testosterone levels and reduced insulin signaling genes indicative of decreased insulin sensitivity. Participants with low testosterone received a weekly testosterone injection or a placebo for 24 weeks. Body weight, body fat, markers of inflammation, insulin sensitivity and other factors were assessed before and after treatment.

At the end of the trial, men who received testosterone experienced a more than six pound average loss of body fat and an equal increase in muscle mass. They also had lower levels of the inflammatory markers C-reactive protein, interleukin-1b and tumor necrosis factor-a. “Most importantly, we saw a dramatic increase in insulin sensitivity, demonstrated by a 32 percent increase in the uptake of glucose by tissues in response to insulin,” Dr Dandona reported.

“Testosterone treatment for men, where indicated, will improve sexual function and increase skeletal muscle strength and bone density,” Dr Dandona noted. “This is the first definitive evidence that testosterone is an insulin sensitizer and hence a metabolic hormone.”